Washing machine having drying function

ABSTRACT

A washing machine having a drying function is disclosed. The washing machine having a drying function may include a tub to receive wash water therein, a drum rotatably provided in the tub, to receive drying objects therein, a heater and a ventilation fan to generate hot air, a dry duct to guide the hot air into the drum, and cooling water supply means to supply cooling water to an outer circumferential surface of the drum to form a condensation surface, on which condensate is generated, on a surface of the drum.

TECHNICAL FIELD

Embodiments may relate to a washing machine having a drying function, more particularly to a washing machine having a drying function that has an improved condensation structure.

BACKGROUND ART

Generally, a washing machine is an electric appliance that is able to remove various contaminants attached to clothes, beddings and wearable items (hereinafter, laundry) by using emulsion action of detergent, friction of water currents generated by rotation of a pulsator or drum and shock applied to laundry. A full-automatic washing machine which is introduced recently performs a series of cycles including washing, rinsing and dry-spinning courses automatically, without a manual operation.

In recent, demands for drum type washing machines have been increasing gradually, because drum type washing machines can reduce an overall height and generate no problems of wrinkles and tangle generated in laundry, compared with pulsator type washing machines.

To put a structure of the drum type washing machine mentioned above simply, the drum type washing machine includes a cabinet which defines an exterior appearance thereof, a tub located in the cabinet, with being supported by a damper and a spring, to receive wash water therein, and a cylindrically-oriented drum located in the tub to receive laundry therein. A driving force is transferred to the drum is by a driving unit to wash the laundry loaded into the drum.

Such the drum type washing machine having the structure mentioned above generates vibration because of a rotational force of the drum generated when it is rotated and eccentricity of the laundry as an inevitable consequence. The vibration generated by the rotation of the drum is transferred outside via the tub and the cabinet.

Because of that, it is necessary to provide the spring and the damper provided between the tub and the cabinet to suspend and dampen the vibration of the tub and to prevent the vibration transferred to the tub from the drum from transferred to the cabinet.

In the meanwhile, the drum type washing machine mentioned above is installed in an existing installation environment (for example, a sink environment or a built-in environment), not installed separately. As a result, the dimension of the drum type washing machine has to be limited by an installation environment.

It is limited to change an internal structure of such the drum type washing machine for the structure of the spring and damper provided between the tub and the cabinet to suspend and dampen the vibration, as mentioned above. Also, it is limited to change the dimension of the washing machine, because the installation environment of the drum type washing machine is limited.

A lot of searches and developments have been in progress about increase of a washing capacity of the washing machine to improve the quantity of washing objects and users' convenience recently. However, it is quite difficult in the structure of the conventional drum type washing machine to improve the dimension of the tub to improve the washing capacity, because of the limited conditions mentioned above.

In the meanwhile, the washing machine may be classified into a washing-only device with only a washing function and a washing machine with a drying function.

The washing machine having the drying function may be classified based on the structure or type into a drum type drying machine capable of drying laundry through rotating and tumbling of the laundry performed by a rotatable drum and a cabinet type drying machine capable of drying the laundry that is hung therein.

The drum type washing machine having the drying function may include a cabinet which defines an exterior appearance thereof, a tub mounted in the cabinet and a drum rotatably mounted in the tub.

In addition, there may be provided in an outer side of the tub a dry duck where dry air is circulated, a heater and a ventilation fan which are installed in the dry duck and a condensation duct where damp air used in drying is circulated and condensed. Auxiliary air-cooled or water-cooled means used for condensation may be provided in the condensation duct.

However, such the conventional drum type drying machine has to include an auxiliary condensation duct. Because of the condensation duct, an inner structure of the cabinet might be complex and the production cost might increase disadvantageously.

DISCLOSURE OF INVENTION Technical Problem

To solve the problems, an object of the embodiments is to provide a washing machine having a drying function which can increase the capacity of a tub in a state of maintaining an exterior size applied to a conventional washing machine and which can improve a supporting structure capable of supporting the capacity-increased tub effectively.

Another object of the embodiments is to provide a washing machine having a drying function that can effectively condense humid air without an auxiliary condensation duct.

Solution to Problem

To achieve these objects and other advantages and in accordance with the purpose of the embodiments, as embodied and broadly described herein, a washing machine having a drying function includes a tub to receive wash water therein; a drum rotatably provided in the tub, to receive drying objects therein; a heater and a ventilation fan to generate hot air; a dry duct to guide the hot air into the drum; and cooling water supply means to supply cooling water to an outer circumferential surface of the drum to form a condensation surface, on which condensate is generated, on a surface of the drum.

The cooling water supplied by the cooling water supply means may be supplied out of the wash water supplied to the tub.

The washing machine having the drying function may further include a water supply hose to supply wash water to the tub; and a branched hose branched from the water supply hose, to supply the cooling water.

The branched hose may be connected with an outer circumferential surface of the tub.

The washing machine having the drying function may further include a spray nozzle provided in an inner circumferential surface of the tub, to diffusively spray the cooling water supplied from the branched hose toward an outer circumferential surface of the drum.

The condensation surface may be formed by a cooling surface where the cooling water is sprayed.

A plurality of through holes to discharge the wash water there through may be formed in an outer circumferential surface of the drum, and the size of the through hole formed in the cooling surface may be smaller than the size of the through hole formed in the other areas except the cooling surface.

A plurality of through holes to discharge the wash water there through may be formed in the cooling surface, and each of the through holes may have the size large enough not to pass the cooling water there through because of the weight of the cooling water.

A plurality of through holes to discharge the wash water there through may be formed in the cooling surface, and each of the through holes may have the size large enough not to pass the cooling water there through because of a wind pressure of the hot air.

A plurality of through holes to discharge the wash water there through may be formed in the cooling surface, and each of the through holes may have the size large enough not to pass the cooling water there through because of a centrifugal force of the drum.

The drum may be rotated at a predetermined velocity to prevent the cooling water from being drawn into the drum, as soon as the cooling water is supplied.

The rotation velocity of the drum may be a predetermined velocity before the drying objects are in close contact with an inner wall of the drum.

The rotation velocity of the drum may be in a rage of 40˜110 rpm.

The cooling water may fall to an outer circumferential surface of the drum, spaced apart a predetermine distance from a rotation center of the drum.

The drum may be rotated in an opposite direction of the falling direction of the cooling water toward the drum.

The washing machine having the drying function may further include a hot air outlet provided in an outer circumferential surface of the tub, to re-supply air inside the tub to the dry duct.

The washing machine having the drying function may further include a filter provided in an inner circumferential surface of the tub, in communication with the hot air outlet.

The washing machine having the drying function may further include a filter cleaning member provided in the hot air outlet to spray cleaning water to the filter.

The cooling water supply means may be the filter cleaning member which supplies the cleaning water.

The washing machine having the drying function may further include a shaft connected with the drum; a bearing housing to rotatably support the shaft; a motor to rotate the shaft; and a suspension unit connected with the bearing housing, to suspend vibration of the drum.

The washing machine having the drying function may further include a driving unit comprising a shaft connected with the drum, a bearing housing to rotatably support the shaft and a motor to rotate the shaft; and a sealing member which seals a rear of the tub to prevent water from leaking to the driving unit from the tub, the sealing member allowing the driving unit to relatively move with respect to the tub.

The washing machine having the drying function may further include a suspension unit which supports the drum, wherein the tub is supported more rigidly than the drum is supported by the suspension unit.

In the meanwhile, according to an embodiment of the washing machine, a suspension assembly may be connected with a driving unit to suspendingly support the vibration of the drum. In the conventional washing machine, the suspension assembly is connected with the tub to suspend the vibration of the tub and the drum together. The washing machine according to the embodiments may have a structure that the vibration of the drum is separate from that of the tub. The suspension assembly may include a radial direction bracket extended in a radial direction, connected with a bearing housing, and a shaft direction bracket extended in a forward direction or a direction toward a shaft of the drum, connected with the radial direction brackets. The pair of the radial direction brackets and the pair of the shaft direction brackets may be provided side to side. A suspension unit may be provided and the suspension unit may include a plurality of suspensions connected with the shaft direction bracket or the bearing housing.

In the meanwhile, the tub may be supported more rigidly than the drum is supported by the suspension assembly. Examples of the structure that supports the tub more rigidly than the suspension assembly will be described as follows.

First, a predetermined area of the tub may be integrally formed with the cabinet.

Second, the tub may be connectedly supported by the cabinet, using a screw, a rivet and rubber bushing or fixedly supported, using welding and adhesive sealing. In this case, a rigidity of such a connection member may be larger than the rigidity of the suspension assembly with respect to a vertical direction that is a main vibration direction of the drum.

In the meanwhile, a flexible member may be provided to reduce the vibration of the drum that is transferred to the tub. The flexible member may prevent water leakage toward a driving unit and the tub and it may connect the tub and the driving unit with each other flexibly, to allow the driving unit to relatively move with respect to the tub. The flexible member may be a rear gasket.

Advantageous Effects of Invention

The embodiments have following advantageous effects. According to the washing machine according to the embodiments, the capacity of a tub may be increased in a state of maintaining an exterior size applied to a conventional washing machine and a supporting structure capable of supporting the capacity-increased tub effectively may be improved.

Furthermore, there may be an effect of condensing humid air effectively without an auxiliary condensation duct.

BRIEF DESCRIPTION OF DRAWINGS

Arrangements and embodiments may be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein:

FIG. 1 is an exploded perspective view illustrating a washing machine having a drying function according to an embodiment;

FIG. 2 is a perspective view illustrating a tub provided in the washing machine having the drying function shown in FIG. 1;

FIG. 3 is a perspective view illustrating an inner structure of the tub provided in the washing machine having the drying function according to the embodiment;

FIGS. 4 and 5 are sectional views illustrating a condensation structure of the washing machine having the drying function;

FIG. 6 is a perspective view illustrating a tub provided in a washing machine having a drying function according to another embodiment;

FIGS. 7 and 8 are sectional views illustrating a filter cleaning member provided in the washing machine having the drying function according to the embodiment shown in FIG. 6;

FIG. 9 is a diagram schematically illustrating a drum provided in the washing machine according to the embodiments; and

FIG. 10 is an enlarged view schematically illustrating key parts of the drum provided in the washing machine according to the embodiments.

BEST MODE FOR CARRYING OUT THE INVENTION

As follows, embodiments will be described in detail in reference to the accompanying drawings.

Reference may now be made in detail to specific embodiments, examples of which may be illustrated in the accompanying drawings. Wherever possible, same reference numbers may be used throughout the drawings to refer to the same or like parts.

As shown in FIG. 1, a washing machine having a drying function according to an embodiment may include a cabinet 10 for forming an exterior appearance thereof, a tub 100 provided in the cabinet 10, and a drum 500 rotatably provided in the tub 100 to receive drying objects therein. The washing machine according to embodiments may have the tub 100 that is fixedly supported by the cabinet 10.

A configuration for the drying function may include a dry duct 200 where high-temperature-dry air is circulated and a heater 220 and a ventilation fan 210 that are provided in the dry duct 200 to heat and ventilate air. The tub 100 may include a tub front 100 and a tub rear 120 that define front and rear sides thereof, respectively, and a tub back 130 that defines a rear wall of the tub rear 120.

An opening may be formed in a rear side of the tub rear 120 and a rear gasket 400 formed of a flexible member may be coupled to the opening. The rear gasket 400 may be coupled to the tub back 130 inwardly along a radial direction. A shaft 560, which will be described later, may pass through the tub back 130.

The rear gasket 400 may be sealed to be connected with the tub back 130 and the tub rear 120, to prevent wash water inside the tub 100 from leaking. The tub back 130 may be vibrated together with the drum 500 when the drum 500 is rotated. However, the rear gasket 400 may be flexible and it may allow to the tub back 130 to move relatively, without being interfered with by the tub rear 120. The rear gasket 400 may include a curvature part or a corrugation part which is extendible by an enough length to allow the relative movement of the tub back 130.

The drum 500 may include a drum front 510, a drum center 520 and a drum back 530. Balancers 540 may be arranged in front and rear areas of the drum 500, respectively. The drum back 530 may be connected with a spider 550 and the spider 550 may be connected with a shaft 560. The drum 500 may be rotated within the tub 100 by a rotational force transmitted via the shaft 560. A plurality of through-holes (502, see FIG. 8) may be formed in a circumferential surface of the drum 500 to discharge the water generated from the laundry during the washing or spinning outside.

A bearing housing 600 may be coupled to a rear surface of the tub back 130. The bearing housing 600 may rotatably support the shaft 560, located between a motor and the tub back 130. The bearing housing 600 may be supported by a suspension unit (300, see FIG. 1) with respect to a base of the cabinet 10.

The suspension unit 300 may include three perpendicular dampers 310 and two slope dampers 320 that support the bearing housing 600 obliquely with respect to a forward and rearward direction. The suspension unit 300 may be flexibly connected with the case (not shown) of the cabinet 10 to allow the drum 500 to flexibly move in forward/rearward and rightward/leftward directions, not fixedly connected with the base of the cabinet 10.

In other words, the suspension unit 300 may be flexibly supported to allow the movement of the drum 500 along forward/rearward and rightward/leftward directions with respect to supporting points connected with the base. The three perpendicular suspensions provided for the flexible support may be arranged in the base of the cabinet 10 by using rubber bushing.

Here, the three perpendicular dampers 310 arranged perpendicularly out of the suspension unit 300 may be spring cylinder dampers to suspend the vibration of the drum 500 and the two slope dampers 320 arranged obliquely may be cylinder dampers to damp the vibration.

In other words, the perpendicular suspensions may be employed as springs and the slope suspensions may be employed as damping means in a vibration system including the spring and damping means.

As mentioned above, the tub 100 according to the embodiment may be fixedly disposed in the cabinet 10 and the vibration of the drum 500 is suspendedingly supported by the suspension unit 300. Substantially, the structure of the tub 100 and the drum 500 may be separate in the washing machine. It can be said that the washing machine according to this embodiment has the structure that the tub 100 may not be vibrated structurally, even when the drum 500 is vibrated.

In the meanwhile, as shown in FIGS. 2 and 3, a hot air inlet 140 may be formed in an upper front area of the tub 100 and a hot air outlet 150 may be formed in an upper rear area of the tub, near a side surface.

The hot air inlet 140 may be formed in the upper front area of the tub 100 to be positioned in front of a front opening of the drum 500. The hot air inlet 140 and the hot air outlet 150 may be almost in parallel to allow directions of the hot air to form an angle of 10 degrees or less. The hot air inlet 140 and the hot air outlet 150 may be in communication with each other via the dry duct 200.

The dry duct 200 may be provided in a top area of the tub 100 and both ends of the dry duck 200 may be in direct communication with the tub 100. The washing machine according to the embodiment may include no condensation duct, different from the conventional washing machine, and a circulation passage along the order of ‘dry duct-drum-tub-dry duct’.

The dry duct 200 may be connected with the hot air inlet 140 and the hot air outlet 150. A ventilation fan 210 to ventilate air to the drum 500 and a heater 220 to heat the ventilated air may be arranged in the dry duct 200.

As the ventilation fan 210 is driven, the internal air of the tub 100 drawn into the hot air outlet 150 may be drawn into the dry duct 200. After that, the air may be heated in the dry duct 200 and it may be re-drawn into the tub 100 and the drum 500 via the hot air inlet 140.

In the meanwhile, the hot air passing the wet laundry inside the drum 500 may contain foreign matters such as lint. A filter (173, see FIGS. 3 and 7) may be arranged to filter such foreign matters.

The filter 173 may be arranged in an exposed area of the tub 100 as shown in FIG. 7. Especially, the filter 173 may be positioned in a circumferential surface of the tub 100 and it may be extended along an inner circumferential surface of the tub 100, under the hot air outlet 150.

In the meanwhile, once the drum 500 is rotated, rotating air current may be formed near the drum 500 by the rotation of the drum 500. The foreign matters such as lint stuck to the filer 173 may be removed while the rotating air current is colliding with the filter 173.

Here, when the wet laundry is located in the drum 500, the water may be emitted to an inner wall surface of the tub 100 from the laundry via the through holes 502 of the drum 500. The emitted water may collide with the filter 173 and it may enhance a washing effect of the filter 173.

In the meanwhile, a filter cleaning member 170 may be further provided to supply water to the filter 173 to enhance the washing effect of the filter 173 more. For that, a branched hose 183 may be branched from a water supply hose 180 provided to supply water to the tub 100 to be connected with a water supply hole 152 of the hot air outlet 150.

Here, the water supplied via the branched hose 183 may be supplied to an outer surface in opposite to the inner surface toward the inside of the tub 100. The supplied water may flow into the tub 100, with cleaning the filter 173.

The water used for cleaning the filter 173 may be supplied together with the wash water supplied to the tub 100. Alternatively, a valve (not shown) may be provided at a branched point of the branched hose 183 or in the branched hose 183. The point of the water supply to the filter may be controlled by the valve.

The washing machine having the drying function according to the embodiment may include a circulation type drying system that circulates hot air without a condensation duct provided outside the tub 10 in the conventional washing machine. In other words, the conventional washing machine having the drying function includes an auxiliary condensation duct used to generate condensate. However, the washing machine having the drying function according to the embodiment generates condensate on a surface of the drum 500 by using a surface, specifically, an outer surface of the drum 500 as a condensation surface, without the auxiliary condensation duct.

For that, cooling water may be used to cool the drum 500 in the washing machine according to this embodiment. Here, the cooling water may be the wash water supplied for the washing, the water supplied to clean the filter or cooling water additionally supplied for the cooling of the drum 500.

As follows, the condensation system of the washing machine having the drying function according to the embodiment as mentioned above will be described in detail.

In reference to FIGS. 2 to 5, an embodiment will be described that the water supplied as wash water is used for cooling the drum 500 to generate condensate on the drum 500.

The washing machine having the drying function according to this embodiment shown in FIGS. 2 and 4 includes a water supply hose 180 to supply the wash water used for the washing. The water supply hose 180 may supply the wash water to the tub 100 via a detergent box which is not shown in the drawings.

Here, the water supply hose 180 connected with the tub 100 may be connected to a front surface or an outer circumferential surface of the tub 100 according to this embodiment. Alternatively, the water supply hose 180 may be branched to be connected with the front and outer circumferential surfaces of the tub. If the water supply hose 180 is branched, a valve (not shown0 may be further provided in each of the branched hoses to open and close a passage of the wash water.

In the meanwhile, the wash water supplied via the water supply hose 180 connected with the outer circumferential surface of the tub 100 may fall to an outer circumferential surface of the drum 500 positioned in the tub 100. In other words, the water supply hose 180 connected with the outer circumferential surface of the tub 100 may be positioned beyond the drum 500.

A spray nozzle (176, see FIG. 9) configured to spray the water supplied from the water supply hose 180 may be further provided at an end of the water supply hose 180 positioned beyond the drum 500. The wash water is dispersedly sprayed to the outer circumferential surface of the drum 500, to cool the surface of the drum 500 more broadly and quickly.

In the meanwhile, the wash water falling to the outer circumferential surface of the drum 500 may be stored in the tub 100 to be used for the washing of the laundry as the wash water after flow along the outer circumferential surface of the drum 500, when the washing of the laundry is performed. However, when the drying of the laundry is performed, the wash water that falls on the outer circumferential surface of the drum 500 may decrease the temperature of the drum 500 to allow the drum used as a condensation plate.

As follows, an embodiment of the drying process mentioned above will be described in detail.

First of all, dry air that is heated by the ventilation fan 210 and the heater provided in the dry duct 200 may be supplied to the drum 500 via the hot air inlet 140, as the drying process is performed. The dry air supplied to the drum 500 may be re-circulated into the dry duct 200 via the hot air outlet 150.

In the process mentioned above, the dry air may be discharged between the drum 500 and the tub 100 via the through holes 502 formed in the drum 500 after drawn into the drum from the front of the drum 500 to dry the laundry.

The high temperature dry air drawn into the drum 500 may contact the wet drying objects received in the drum 500 and it takes the moisture from the drying objects to dry them. In this process, the high temperature dry air may be changed into low temperature moist air and the low temperature moist air may be discharged outside the drum 500 via the through holes 502 formed in a wall surface of the drum 500.

The air discharged outside the drum 500 may flow between the tub 100 and the drum 500, to be discharged outside the tub 100 via the hot air outlet 150 formed in the rear of the tub rear 120.

At this time, cooling water is supplied to the outer circumferential surface of the drum 500, to improve the condensation effect. The supply of the cooling water may be performed by using the supply passage of the wash water. In other words, the wash water is supplied via the supply passage of the wash water, to contact with the drum 500 to cool the drum 500. At this time, the less quantity of the water may be supplied than the quantity of the wash water used in the washing. In other words, the quantity of the water enough only to wet the surface of the drum 500 may be supplied, to prevent the leakage into the drum 500 (the space where the drying objects are positioned).

In case the supply location of the cooling water (the location of the spray nozzle 176) is eccentric with respect to the center of the drum 500, the supplying point of the cooling water may be at the moment when the rotation direction of the drum 500 is opposite to the direction of the cooling water supply. This is because the cooling water can be diffused broadly on the surface of the drum 500 for a relatively long time along the rotation direction of the drum when the rotation direction of the drum 500 is opposite to the supply direction of the cooling water, to maintain the cooling time of the drum for a long time.

As a result, the outer wall of the drum 500 may maintain a relatively lower temperature than the temperature inside the drum because of the water supplied via the water supply hose (or the spray nozzle).

As follows, a condensation system of a washing machine having a drying function according to another embodiment will be described in detail.

According to another embodiment, the water supplied as filter cleaning water may be used to cool the drum 500 and to generate condensate on the drum 500.

In reference to FIGS. 6 to 8, the washing machine having the drying function according to the embodiment may include a filter 173 provided to filter lint generated during the drying and a filter cleaning member 170 outer to the filter 173 to remove the lint filtered by the filter 173. Here, the filter 173 may be formed to correspond to an extended line of an inner circumferential surface of the tub 100 on a passage of a hot air outlet 150 through which air is discharged. The filter cleaning member 170 may spray cleaning water into the tub 100 from an inside of the hot air outlet 150.

Here, the cleaning water to the filter cleaning member 170 may be supplied by a branched hose 183 branched from the water supply hose 180. The branched hose 183 may be branched from the water supply hose 180 and it may be extended into the hot air outlet 150, such that the wash water toward the inside of the tub 100 from the inside of the hot air outlet 150 may be sprayed to clean the filter 173.

At this time, in case the branched hose 183 is branched from the water supply hose 180, a valve (not shown) may be further provided in the branched hose to open and close the passage of the cleaning water.

In the meanwhile, the cleaning water supplied from the filter cleaning member 170 may be drawn into the tub 100, after passing the filter 173. Here, the filter 173 may be positioned above the drum 500 and the cleaning water after passing the filter 173 may fall on an upper outer circumferential surface of the drum 500. Also, the cleaning water used for cleaning the filter 173 may be sprayed with a predetermined pressure, to clean the filter 173. The cleaning water sprayed with the predetermined pressure may be diffused by a net-shaped filter, while passing the filter 173 and it may cool a surface of the drum 500 more broadly and quickly.

In other words, the cleaning water supplied from the filter cleaning member 170 may be employed as the cleaning water used to remove lint remaining in the filter 173 when the cleaning the filter 173. However, the cleaning water falling to the outer circumferential surface of the drum 500 may be employed for lowering the temperature of the drum 500 to allow the drum to be a condensation plate.

As follows, a drying process according to another embodiment will be described in detail.

As the drying process is performed, the dry air heated by the ventilation fan 210 and the heater 220 provided in the dry duct 200 may be supplied to the inside of the drum 500 via the hot air inlet 140 and the dry air supplied to the drum 500 may be re-circulated into the dry duct 200 via the hot air outlet 150.

In the drying process mentioned above, the dry air may be drawn into the drum 500 to be used for drying the drying objects, and then discharged between the drum 500 and the tub 100 via the through holes 502 formed in the drum.

The high temperature dry air drawn into the drum 500 may take the moisture from the drying objects by contacting with the moist drying objects, to dry them. In this process, the high temperature dry air may be discharged outside the drum 500 via the through holes 502 formed in a wall surface of the drum 500, in a state of being low temperature humid air.

The air discharged outside the drum 500 may flow between the tub 100 and the drum 500, to be discharged outside the tub 100 via the hot air outlet 150 formed in the rear of the tub rear 120.

At this time, cooling water may be supplied to an outer circumferential surface of the drum 500 and a condensation effect may be enhanced. The supply of the cooling water may be performed by using cleaning water supplied from the filter cleaning member 170. In other words, the wash water is supplied via the supply passage of the wash water, and then the cleaning water for cleaning the filter 173 may be sprayed to an outer circumferential surface of the drum 500, to cool the drum 500. At this time, the quantity of the cleaning water may be more or less than the quantity of the cleaning water used for cleaning the filter the washing. In other words, the quantity of the cleaning water enough only to wet the surface of the drum 500 may be supplied, to prevent the leakage into the drum 500 (the space where the drying objects are positioned).

In case the supply location of the cooling water of the filter 173 or the filter cleaning member (or the location of the spray nozzle 176) is eccentric with respect to the center of the drum 500, the supplying point of the cooling water may be at the moment when the rotation direction of the drum 500 is opposite to the direction of the cooling water supply. This is because the cooling water can be diffused broadly on the surface of the drum 500 for a relatively long time along the rotation direction of the drum when the rotation direction of the drum 500 is opposite to the supply direction of the cooling water, to maintain the cooling time of the drum for a long time.

As a result, the outer wall of the drum 500 may maintain a temperature relatively much lower than the temperature inside the drum 500 because of the cleaning water supplied from the filter cleaning member 170.

In the meanwhile, in case the drum 500 is cooled by supplying the cooling water (the wash water or the cleaning water) to the outer circumferential surface of the drum 500 as mentioned above, the cooling water supplied to the outer circumferential surface of the drum 500 happens to be drawn into the drum via the through holes 502 formed in the drum. In this case, the cooling water supplied to generate the condensate contacts the laundry having the drying process and the laundry might be wet. Because of that, the drying effect might deteriorate.

To solve the disadvantage, a structure configured to prevent the cooling water from flowing into the drum 500 via the through holes 502 formed in the drum 500 will be described in reference to FIGS. 9 and 10.

As shown in the drawings, typically the drum 500 may be rotatable in the tub 100. The plurality of through holes 502 may be formed in the outer circumferential surface of the drum 500 to discharge the wash water generated from the laundry or the drying objects.

The cooling water (for example, the wash water or the cleaning water, hereinafter, “the cooling water”) supplied to the outer circumferential surface of the drum 500 during the drying process might be drawn through such through holes 502. In the meanwhile, the cooling water sprayed toward the outer circumferential surface of the drum 500 may be sprayed to a predetermined area of the outer circumferential surface of the drum 500. Here, the predetermined area where the cooling water is sprayed may be a cooling surface (A). As a result, the cooling water may not be drawn via all of the through holes 502 formed in a front surface of the drum 500. Because of that, the cooling water might be drawn through only some of the through holes 502 formed in the cooling surface (A) where the cooling water is sprayed.

The sizes of the through holes 502 formed in the cooling surface (A) of the drum 500 where the cooling water may be drawn may be adjusted, to prevent the cooling water from being drawn. Here, a condition of the size of the through hole 502 which may not pass the cooling water there through may be changeable by a surface tension of the through hole 502, that is, the weight of the cooling water.

Here, equations of the hole surface tension (Hst) will be following [EQUATION 1]:

Hst=

×2πr _(hole)  [EQUATION 1]

Here, “

” refers to a surface tension coefficient and “r_(water)” refers to a diameter of the through hole 502. The weight of the cooling water may be following [EQUATION 2]:

$\begin{matrix} {{Wg} = {\frac{\rho_{water}4\pi \; r_{water}^{3}}{3} \times G}} & \left\lbrack {{EQUATION}\mspace{14mu} 2} \right\rbrack \end{matrix}$

Here, “ρ_(water)” refers to a specific gravity of water and “r_(water)” refers to a radius of a cooling water-drop. “G” refers to the acceleration of gravity.

As a result, the condition that makes the cooling water-drop not drawn into the through hole 502 of the drum 500 based on [EQUATION 1] and [EQUATION 2] (in other words, the maximum radius of the through hole 502) may be calculated based on following [EQUATION 3]:

$\begin{matrix} {{{Hst} \geq {Wg}}{{\gamma \times 2\pi \; r_{water}} \geq {\frac{\rho_{water}4\pi \; r_{hole}^{3}}{3} \times {G\left( \frac{3\gamma}{2\; \rho \; G} \right)}^{\frac{1}{2}}} \geq r}} & \left\lbrack {{EQUATION}\mspace{14mu} 3} \right\rbrack \end{matrix}$

According to [EQUATION 3], the diameter (

) of the through hole 502 that is large enough for the cooling water-drop not to be drawn through may be calculated.

However, the drum 500 may be rotated at a preset velocity when the drying is performed and the diameter of the through hole 502 may be changed more by a wind pressure of the dry air supplied to the tub 100 as well as the condition based on [EQUATION 3] mentioned above. In other words, the condition of the drawing into the through hole of the drum 500 may be changed by the wind pressure of the dry air, in case of the cooling water drawn through the through hole of the drum 500. The diameter of the through hole 502 calculated based on [EQUATION 2] may be a minimum diameter enough not to draw the cooling water through the through hole.

As a result, the wind pressure (Wp) of the dry air supplied to the tub 100 may be calculated based on following [EQUATION 4].

$\begin{matrix} {{WP} = {\frac{\rho_{air}V^{2}}{2} = \frac{{\rho_{air}\left( {r_{drum}\theta} \right)}^{2}}{2}}} & \left\lbrack {{EQUATION}\mspace{14mu} 4} \right\rbrack \end{matrix}$

[EQUATION 4] is applied to [EQUATION 2] to get following [EQUATION 5].

$\begin{matrix} {{\left( {\gamma \times 2\pi \; r_{water}} \right) + \frac{{\rho_{air}\left( {r_{drum}\theta} \right)}^{2}}{2}} \geq {\frac{\rho_{water}4\pi \; r_{hole}^{3}}{3} \times G}} & \left\lbrack {{EQUATION}\mspace{14mu} 5} \right\rbrack \end{matrix}$

As a result, considering the condition of the wind pressure applied to the diameter of the through hole 502 calculated based on [EQUATION 2], the through hole 502 formed in the drum 500 formed of a stainless material typically may have a radius of 2˜3 mm. The cooling water may not be drawn into the through hole having a radius of 2.7 mm. However, considering the wind pressure condition of the dry air, the diameter of the through hole 502 may be enlarged when the wind pressure condition is increased.

As mentioned above, the position and the size of the through hole 502 formed in the drum may be adjusted, and it may be then prevented that the cooling water sprayed or falling toward the surface of the drum is drawn into the drum 500.

Alternatively, the rotation velocity of the drum 500 may be increased to prevent the wash water supplied to the outer circumferential surface of the drum 500 from being drawn into the drum 500 via the through holes 502. Here, the drum 500 may be rotated at a predetermined rotation velocity high enough for the wash water remaining on the outer circumferential surface of the drum 500 not to be drawn into the drum 500 via the through holes 502.

For example, the rotation velocity of the drum 500 may be maintained in a range of 40˜110 rpm during the drying process. Preferably, the rotation velocity of the drum 500 may be 5070 rpm. Typically, when the drum 500 has a rotation velocity of 110 rpm or more, the laundry received in the drum 500 may be rotated in close contact with an inner circumferential surface of the drum 500. In this case, the laundry might not be mixed with the dry air effectively and drying efficiency might be deteriorated. As a result, the rotation velocity of the drum 500 may be equal to 110 rpm or less. In other words, the rotation velocity has to be maintained high enough to rotate the laundry not in close contact with the inner circumferential surface of the drum 500, to mix the laundry and the dry air.

As a result, a centrifugal force of the drum 500 as the drum 500 is rotated may prevent the wash water remaining on the outer circumferential surface of the drum 500 (that is, the wash water supplied to cool the drum 500) from being drawn into the drum 500 via the through holes 502.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to affect such feature, structure, or characteristic in connection with other ones of the embodiments. Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

1. A washing machine having a drying function comprising: a tub to receive wash water therein; a drum rotatably provided in the tub, to receive drying objects therein; a heater and a ventilation fan to generate hot air; a dry duct to guide the hot air into the drum; and cooling water supply means to supply cooling water to an outer circumferential surface of the drum to form a condensation surface, on which condensate is generated, on a surface of the drum.
 2. The washing machine having the drying function of claim 1, wherein the cooling water supplied by the cooling water supply means is supplied out of the wash water supplied to the tub.
 3. The washing machine having the drying function of claim 2, further comprising: a water supply hose to supply wash water to the tub; and a branched hose branched from the water supply hose, to supply the cooling water.
 4. The washing machine having the drying function of claim 3, wherein the branched hose is connected with an outer circumferential surface of the tub.
 5. The washing machine having the drying function of claim 3, further comprising: a spray nozzle provided in an inner circumferential surface of the tub, to diffusively spray the cooling water supplied from the branched hose toward an outer circumferential surface of the drum.
 6. The washing machine having the drying function of claim 5, wherein the condensation surface is formed by a cooling surface where the cooling water is sprayed.
 7. The washing machine having the drying function of claim 6, wherein a plurality of through holes to discharge the wash water there through are formed in an outer circumferential surface of the drum, and the size of the through hole formed in the cooling surface is smaller than the size of the through hole formed in the other areas except the cooling surface.
 8. The washing machine having the drying function of claim 6, wherein a plurality of through holes to discharge the wash water there through are formed in the cooling surface, and each of the through holes has the size large enough not to pass the cooling water there through because of the weight of the cooling water.
 9. The washing machine having the drying function of claim 6, wherein a plurality of through holes to discharge the wash water there through are formed in the cooling surface, and each of the through holes has the size large enough not to pass the cooling water there through because of a wind pressure of the hot air.
 10. The washing machine having the drying function of claim 6, wherein a plurality of through holes to discharge the wash water there through are formed in the cooling surface, and each of the through holes has the size large enough not to pass the cooling water there through because of a centrifugal force of the drum.
 11. The washing machine having the drying function of claim 1, wherein the drum is rotated at a predetermined velocity to prevent the cooling water from being drawn into the drum, as soon as the cooling water is supplied.
 12. The washing machine having the drying function of claim 11, wherein the rotation velocity of the drum is a predetermined velocity before the drying objects are in close contact with an inner wall of the drum.
 13. The washing machine having the drying function of claim 11, wherein the rotation velocity of the drum is in a rage of 40˜110 rpm.
 14. The washing machine having the drying function of claim 11, wherein the cooling water falls to an outer circumferential surface of the drum, spaced apart a predetermine distance from a rotation center of the drum.
 15. The washing machine having the drying function of claim 14, wherein the drum is rotated in an opposite direction of the falling direction of the cooling water toward the drum.
 16. The washing machine having the drying function of claim 1, further comprising: a hot air outlet provided in an outer circumferential surface of the tub, to re-supply the air of the tub in the dry duct.
 17. The washing machine having the drying function of claim 16, further comprising: a filter provided in an inner circumferential surface of the tub, in communication with the hot air outlet.
 18. The washing machine having the drying function of claim 17, further comprising: a filter cleaning member provided in the hot air outlet to spray cleaning water to the filter.
 19. The washing machine having the drying function of claim 18, wherein the cooling water supply means is the filter cleaning member which supplies the cleaning water.
 20. The washing machine having the drying function of claim 1, further comprising: a shaft connected with the drum; a bearing housing to rotatably support the shaft; a motor to rotate the shaft; and a suspension unit connected with the bearing housing, to suspend vibration of the drum.
 21. The washing machine having the drying function of claim 1, further comprising: a driving unit comprising a shaft connected with the drum, a bearing housing to rotatably support the shaft and a motor to rotate the shaft; and a sealing member which seals a rear of the tub to prevent water from leaking to the driving unit from the tub, the sealing member allowing the driving unit to relatively move with respect to the tub.
 22. The washing machine having the drying function of claim 1, further comprising: a suspension unit which supports the drum, wherein the tub is supported more rigidly than the drum is supported by the suspension unit. 